The present invention relates to a power conditioning apparatus capable of providing an uninterruptable supply of conditioned electrical power generated using a choice of energy sources. More particularly, the present invention is directed to a method of storing energy in the form of a compressed gas for later use in generating conditioned power, wherein the energy so stored may be selectively obtained from an electrical grid or from a fossil fuel depending on the relative market costs. The present invention is also capable of load shaping, or load following, in that it is capable of storing power when the load demand is below a predetermined value and supplementing grid power when the load demand is greater than the predetermined value, thereby providing an economic benefit to a user.
Deregulation of the electric and natural gas industries and consequent unbundling of power services will have the effect of creating an energy commodity. As with any commodity, transportation, or transmission, costs will be included in the final product cost. As a commodity, energy will be available in many forms from a variety of sources whose relative costs fluctuate with time. In this environment, the energy consumer would ideally choose his energy source based on the relative source costs. Energy consumers will also have the option of using interruptible power sources which will be priced lower than more reliable sources. The consumer will also be able to purchase power on an uninterruptable or "firm" basis, i.e., a guaranteed amount and availability of power, or on an interruptable or "non-firm" basis, i.e., power without a guarantee as to the amount or availability. As may be expected, non-firm power will be less expensive than firm power. Nevertheless, the increasing use of digital technology will present an ever-increasing need for uninterruptable conditioned electrical power.
Energy consumers thus will require flexibility to take advantage of the coming variety of energy options. One way of achieving flexibility is through tolling. Tolling is the ability to convert from one energy form to another, based on the prevailing spot price of the two energy sources. For example, if the unit spot price of a particular fuel is less than the unit price of electricity by an adequate amount, the owner of the fuel would be rewarded for converting his fuel to electricity for his own use, by selling it, or both. If, on the other hand, electricity prices are much lower than fuel costs, a fuel user would be better served by buying and using electricity.
Energy flexibility will also require the ability to take advantage of interruptible sources. While less expensive than more reliable sources, such sources present a danger to consumers who require uninterrupted, conditioned power. Thus, full advantage of interruptable power is only attainable by consumers with the ability to switch over to a reliable, efficient and economical back-up power source, preferably a self-generating one. Moreover, the switch to back-up power must be made without interruption of the supply to the critical consumer load.
Additionally, due to the expected increase in the number of energy producers, a consumer attempting to maintain the lowest possible energy costs will be required to monitor or somehow determine energy cost prevailing at a given time. This ability to realize the energy costs associated with a producer also should be combined with the ability to access energy from that producer and apply it to the consumer's load as dictated by cost.
It is thus apparent that in the evolving energy commodity market, consumers will need the ability to selectively use multiple energy sources, the ability to monitor and respond to changing energy production characteristics, the ability to convert and store energy for later use, and equipment for providing continuous, uninterrupted conditioned power.